a computer security researcher from kapolei, hawaii... and our returning champion, a logistics director from hockessin, delaware... and now here is the host of "jeopardy!" -- alex trebek! [ cheers and applause ] thanks, johnny. thank you. thank you very much. we are delighted to welcome our challengers today. skylar and noah coming up against a pretty good champion in mike. luck to all three of you. let's go to work right now, shall we? this is the jeopardy! round, and these are the jeopardy! round categories. [ laughter ]